Low Profile Cardiac Valves and Methods of Making and Using Same

ABSTRACT

Transluminally implantable cardiac valves configured for use in cardiac valve replacement and/or cardiac valve exclusion that are capable of percutaneous delivery on low-profile catheters having 15 French size or less. The implantable cardiac valves are fabricated of from a unitary metal material to form a lattice frame support having a main body portion and valve leaflet portion, and a plurality of elongate biasing arm members. A polymer coating or covering is disposed on the valve leaflet portion and the elongate biasing arm members and subtends space between adjacent pairs of elongate biasing arm members to form valve leaflet portions in which the elongate biasing arms and the polymer coating operate to share a mechanical load thereupon.

BACKGROUND OF THE INVENTION

This disclosure pertains generally to biased cells that are configuredto flex in- and out-of-plane upon application of a directional strainapplied to the biased cell. More particularly, the present disclosurepertains to a biased cell configured to move in- and out-of-plane uponapplication of a compressive or expansive force to at least a portion ofthe biased cell. The in- and out-of-plane motion induced by applicationof a directional strain to the biased cell is capable, in turn,transferring the motive force from the biased cell to other structuresjoined, coupled, co-extensive, or communicating with the biased cell.One example of a structure that may be moved by the out-of-plane motionis a biasing arm coupled, joined, or integral with and projecting fromthe biased cell. Out-of-plane motion of the biased cell will cause thebiasing arm projecting from the biased cell to also move out-of-plane.

The present disclosure further includes devices that incorporate one ormore biased cells. Such devices include, for example, medical devices,such as steerable stents, cardiac valves, or orthopedic implants.

In one aspect of the present disclosure, the biased cell is a slotbounded by structural members, such a struts. Each biased cell isconfigured to assume a substantially quadrilateral shape as adirectional strain is applied to the biased cell. Each biased cell isbounded by a pair of first strut members defining a longitudinal axis ofthe biased cell and by a pair of second strut members, which may besubstantially orthogonal to the first strut members, and define opposingends each biased cell. Each biased cell has a closed position in whichthe first and second strut members and the slot have a substantiallyquadrilateral cell shape. At least one spring strut is provided thatextends along a longitudinal axis of the biased cell and is positionedbetween adjacent first strut members and between adjacent second strutmembers. The biased cell also has an open position in which thesubstantially quadrilateral cell deforms with the at least one springstrut extends along a diagonal between opposing included angles of thesubstantially quadrilateral cell. In this manner, when in the openposition, the at least one spring strut divides the quadrilateral cellinto triangles with the at least one spring strut forming a commonhypotenuse of each triangle.

A force applied to opposing corners of the substantially quadrilateralcell having the spring strut extending from each opposing corner willcause flexion of the orthogonal corners not having the spring strutjoined thereto, whereas a force applied to opposing corners of thesubstantially quadrilateral cell not having the spring strut joinedthereto will cause flexion of the orthogonal corners having the springstrut joined thereto. The applied forces may exert an expansive or acompressive force on the respective corners of the biased cell, whichtransfers the applied force to the spring strut, imparting a bendingforce to the spring strut, which, in turn, imparts out-of-plane flexionof sections of the biased cell.

In another variant of the present disclosure a biasing projection, whichis contiguous with the spring strut, extends outwardly from a corner ofthe biased cell and a bending force, either externally applied orinherently applied, such as by shape memory or superelastic propertiesof the material employed for the biasing projection or the biased cell,transfers the bending force to the biased cell to either stabilize thebiasing projection or enhance the bending moment of the biasingprojection.

In a further variant of the disclosure, a transluminal cardiac valve isdisclosed having a plurality of biased cells and biasing projections aspart of and support for a valve leaflet apparatus configured to modulatevalve leaflet opening and closing under the influence of cardiac musclecontraction and relaxation and pressure fluctuations across cardiacvalves.

Hereinafter, all variants of biased cell of the present disclosure willbe collectively referred to as a “biased cell” in the singular orplural.

Each biased cell may be combined with one or more other biased cells toform a larger set of biased cells. Each individual biased cell may becombined with other biased cells in such a manner as to have an additiveor a subtractive quantum of flexion based upon the same applied force.That is, for example, a first biased cell unit may have an arbitraryquantum of flexion having a value of 1, a second biased cell unit mayhave an arbitrary quantum of flexion having a value of 1.5. Joining thefirst biased cell unit with the second biased cell unit will then yieldan additive arbitrary quantum of flexion of 2.5 of the combined biasedcell units. In distinction, joining a second biased cell unit having anarbitrary quantum of flexion having a value of 0.5 when combined withthe first biased cell unit will yield a combined arbitrary quantum offlexion equal to 1.5. In this manner, the degree of flexion based upon acommon force applied to a combination of biased cell units may beattenuated to either enhance or temper the overall degree of flexion ofthe combined biased cell units.

Each biased cell is configured as a substantially quadrilateral celldefined by struts that bound the biased cell. Each of the struts areconfigurable to have either uniform or non-uniform dimensions such thatvariations in width, length, and/or thickness may exist with a singlestrut, from strut-to-strut within a biased cell, or from otherindividual biased cells. It will be appreciated that by providing suchvariations in width, length, and/or thickness, the net mechanicalbehavior of each biased cell will respond differently based upon thedegree or positioning of such variations in width, length, and/orthickness of each individual frame biased cell.

As noted above, each biased cell further includes at least one springstrut extending along a diagonal between opposing included angles of thebiased cell. The spring strut may also have variations in width and/orthickness along a length of the spring strut. For example, the springstrut may have a width and/or thickness that tapers along its lengtheither toward a mid-point along its length or toward each opposing endof the spring strut or along the build axis of the spring strut.Alternatively, the spring strut may have one or more curved sections,hinge regions, strain relief sections or the like, along its length tofacilitate deflection of the spring strut either in-plane orout-of-plane relative to a normal axis of the spring strut uponapplication of an expansive or compressive force to the spring strut.

The biased cells of the present disclosure may have many differentapplications to impart flexion and/or directional movement of a largerstructure into which the complaint biased cells are incorporated. Forexample, implantable cardiac valves intended for use in cardiac valvereplacement and/or cardiac valve exclusion, may make advantageous use ofthe biased cells in forming part of the cardiac valve leaflet apparatus,such as a structural component of the cardiac valve leaflet, to modulateopen and closing forces of the cardiac valve leaflets. As anotherexample, the biased cells are capable of being incorporated into stents,such as intravascular or intraluminal stents, and assist in directionalbending of the stent to facilitate wall apposition against anatomicalluminal wall surfaces. A still further example of a use of the biasedcell their incorporation into steerable catheters.

With particular reference to transluminal implantable cardiac valves,the biased cells of the present disclosure have particular utility ascardiac valve leaflet structural elements and valve leaflet roots,and/or as valve anchors. In particular, the present disclosure pertainsto percutaneously deliverable, transluminal prosthetic cardiac valvescapable of percutaneous delivery on low-profile catheters having 15French size (hereinafter denoted “F”) or less.

Contemporary transluminal cardiac valves are combinations of wholexenograft aortic valves or a metal frame and xenograft valvemanufactured of equine, bovine or porcine pericardium. The xenograftvalve leaflets are decellularized by lyophilization with tannin agentssuch as glutaraldehyde. These conventional valves require the use oflarge bore catheters in the range of 19-22 F (6.3-7.3mm) diameter. Suchlarge bore catheters are prohibitively large for people with relativelysmall femoral arteries, such as children or older people, and requirealternative access approaches such as venous trans-septal, ventriculartransapical, or via a temporary trans-subclavian arterial access graft.Xenografts have the potential risk of prion-vector transmission, such asKreutzfeldt-Jakob disease. The decellularized protein frame is prone tobecome rigid and deformed with time and at least initially can bethrombogenic requiring oral anticoagulation. Xenograft valve tissue mayalso be the source of antigens inducing auto-immune disorder. Xenograftvalve designs often involve a cusp motion-limiting portion of the valvethat intrudes into the aortic root, caging the coronary ostia andlimiting access to subsequent coronary interventions, if needed.Xenograft valves are, therefore, sub-optimal and elimination of animaltissue components in favor of synthetic valve leaflet materials is farmore desirable.

By configuring the transluminal low-profile cardiac valve to bedeliverable in a 15F or less catheter, and having a polymer coating orcovering associated with the biased cells, the cardiac valve of thepresent disclosure solves may of the present difficulties with bothxenograft cardiac valves and synthetic leaflet cardiac valves.

SUMMARY OF THE INVENTION

It is an objective of the present disclosure to provide at least onebiased cell configured to deform in- and out-of-plane and facilitatedirectional deflection of another structure into which the at least onebiased cell is a portion thereof.

It is also an object of the present disclosure to provide a low-profiletransluminal, i.e., 15F or less, self-expanding cardiac valveincorporating the at least one biased cell configured to modulate valveleaflet deflection.

It is a further object of the present disclosure to provide a cardiacvalve composed of a single piece superelastic metal frame forming thevalve body and valve leaflet structure and having a polymer covering atleast partially encapsulating or covering the valve leaflet structure.

It is yet another object of the present disclosure to provide a cardiacvalve having a frame, including biasing projections, configured assupport structures for valve leaflets, that are made of superelasticmetal such as binary, ternary or quaternary nickel-titanium alloys andthe valve leaflets are made of a biocompatible polymer.

It is still another object of the present disclosure wherein the binary,ternary or quaternary superelastic metal is fabricated by physical vapordeposition as a hypotube and then the valve frame and valve leafletsupport structure are fabricated from the hypotube as a single, unitaryand monolithic piece.

It is still a further object of the present invention to configure thevalve frame and valve leaflet structure of the same superelasticmaterial.

It is another further objective of the present disclosure that the valveframe and valve leaflet structure are made of different superelasticmaterials.

It is still another objective of the present disclosure to cover thevalve leaflet structure, including biasing projections, with a polymercovering to form the valve leaflets.

It is yet another further object of the present disclosure that thecardiac valve leaflet structure exhibit chronic fatigue resistance equalto or greater than that exhibited by conventional xenograft cardiacvalves.

It is still yet a further object of the present disclosure that thecardiac valve be capable of chronic repetitive cycles of at least 500million cycles, preferably at least 1 billion cycles, without failure.

It is another objective of the present disclosure to provide a cardiacvalve that is able to achieve the above fatigue profile at valve closingpressures exceeding 100 mm Hg present at the end of left ventricularsystole and at lower pressures at the pulmonary, tricuspid and mitralvalve positions.

It is still another objective of the present disclosure to provide acardiac valve incorporating a biased cell in the cardiac valve that isconfigured to assist opening and/or closing of valve leaflets in thecardiac valve.

These and other objects, features, and advantages of the presentdisclosure will be more apparent to those skilled in the art from thefollowing more detailed description of the monolithic transluminalcardiac valve which is capable of percutaneous deployment on a lowprofile catheter of 15 F or less.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an end perspective view of a first variant of the transluminalcardiac valve in accordance with the present disclosure.

FIG. 2 is a planar view of a biased cell of a valve leaflet framesection of the transluminal cardiac valve in accordance with the presentdisclosure

FIG. 3 is a diagrammatic plan view of a biased cell and biasingprojection in an unstrained state.

FIG. 4 is a diagrammatic side elevational view of the biased cell andbiasing projection in the unstrained state.

FIG. 5 is a diagrammatic plan view of the biased cell and biasingprojection in a strained state.

FIG. 6 is a diagrammatic side elevational view of a biased cell andbiasing projection in its strained state.

FIG. 7A is a diagrammatic side elevational view showing deflection ofthe biasing projection.

FIG. 7B is a diagrammatic side elevational view showing deflectionrecovery of the biasing projection.

FIG. 8 is a diagrammatic side elevational view of a valve and valveleaflets in a closed position in accordance with the present disclosure.

FIG. 9A is a top view of a bicuspid transluminal cardiac valve in aclosed position in accordance with the present invention.

FIG. 9B is a top view of the bicuspid transluminal cardiac valve in anopen position in accordance with the present invention.

FIG. 10A is a top view of a tricuspid transluminal cardiac valve in aclosed position in accordance with the present invention.

FIG. 10B is a top view of the tricuspid transluminal cardiac valve in anopen position in accordance with the present invention.

FIG. 11A is a top view of a quadricuspid transluminal cardiac valve in aclosed position in accordance with the present invention.

FIG. 11B is a top view of the quadricuspid transluminal cardiac valve inan open position in accordance with the present invention.

FIG. 12A is a first end perspective view of the transluminal cardiacvalve structure without polymer covering on the valve leaflets.

FIG. 12B is a second end perspective view of the transluminal cardiacvalve structure without polymer covering on the valve leaflets.

FIG. 13 is a side elevational view of a transluminal cardiac valvewithout a polymer covering on the valve leaflets.

FIG. 14 is a fragmentary plan view of a biased cell and biasingprojections in accordance with the present disclosure.

FIG. 15 is a plan view of a section of the single valve leaflet sectionof the transluminal cardiac valve in accordance with the presentdisclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The terminology used herein is for the purpose of describing exampleembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an,” and “the” may be intended to include theplural forms as well, unless the context clearly indicates otherwise.The terms “comprises,” “comprising,” “including,” and “having,” areinclusive and therefore specify the presence of stated features,integers, steps, operations, cells, and/or components, but do notpreclude the presence or addition of one or more other features,integers, steps, operations, cells, components, and/or groups thereof.The method steps, processes, and operations described herein are not tobe construed as necessarily requiring their performance in the orderdiscussed or illustrated, unless specifically identified as an order ofperformance. It is also to be understood that additional or alternativesteps may be employed.

“Substantially” is intended to mean a quantity, property, or value thatis present to a great or significant extent and less than, more than orequal to total. For example, “substantially vertical” may be less than,greater than, or equal to completely vertical.

“About” is intended to mean a quantity, property, or value that ispresent at ±10%. Throughout this disclosure, the numerical valuesrepresent approximate measures or limits to ranges to encompass minordeviations from the given values and embodiments having about the valuementioned as well as those having exactly the value mentioned. Otherthan in the working examples provided at the end of the detaileddescription, all numerical values of parameters (e.g., of quantities orconditions) in this specification, including the appended claims, are tobe understood as being modified in all instances by the term “about”whether or not “about” actually appears before the numerical value.“About” indicates that the stated numerical value allows some slightimprecision (with some approach to exactness in the value; approximatelyor reasonably close to the value; nearly). If the imprecision providedby “about” is not otherwise understood in the art with this ordinarymeaning, then “about” as used herein indicates at least variations thatmay arise from ordinary methods of measuring and using such parameters.In addition, disclosure of ranges includes disclosure of all values andfurther divided ranges within the entire range, including endpointsgiven for the ranges.

Recitation of ranges of values herein are merely intended to serve as ashorthand method of referring individually to each separate valuefalling within the recited range, unless otherwise indicated herein, andeach separate value is incorporated into the specification as if it wereindividually recited herein.

References to “embodiment” or “variant”, e.g., “one embodiment,” “anembodiment,” “example embodiment,” “various embodiments,” etc., mayindicate that the embodiment(s) or variant(s) of the invention sodescribed may include a particular feature, structure, orcharacteristic, but not every embodiment necessarily includes theparticular feature, structure, or characteristic. Further, repeated useof the phrase “in one embodiment,” or “in an exemplary embodiment,” donot necessarily refer to the same embodiment or variant, although theymay.

As used herein the term “method” refers to manners, means, techniquesand procedures for accomplishing a given task including, but not limitedto, those manners, means, techniques and procedures either known to, orreadily developed from known manners, means, techniques and proceduresby practitioners of the chemical, pharmacological, biological,biochemical and medical arts. Unless otherwise expressly stated, it isin no way intended that any method or aspect set forth herein beconstrued as requiring that its steps be performed in a specific order.Accordingly, where a method claim does not specifically state in theclaims or descriptions that the steps are to be limited to a specificorder, it is in no way intended that an order be inferred, in anyrespect. This holds for any possible non-express basis forinterpretation, including matters of logic with respect to arrangementof steps or operational flow, plain meaning derived from grammaticalorganization or punctuation, or the number or type of aspects describedin the specification.

The term “metal material” is intended to refer to metals, alloyed metalsor pseudometals.

For purposes of this application, the terms “pseudometal” and“pseudometallic” are intended to mean materials which exhibit materialcharacteristics substantially the same as metals. Examples ofpseudometallic materials include, without limitation, compositematerials, polymers, and ceramics. Composite materials are composed of amatrix material reinforced with any of a variety of fibers made fromceramics, metals, carbon, or polymers.

As used in this application the term “layer” is intended to mean asubstantially uniform material limited by interfaces between it andadjacent other layers, substrate, or environment. The interface regionbetween adjacent layers is an inhomogeneous region in which extensivethermodynamic parameters may change. Different layers are notnecessarily characterized by different values of the extensivethermodynamic parameters but at the interface, there is a local changeat least in some parameters. For example, the interface between twosteel layers that are identical in composition and microstructure may becharacterized by a high local concentration of grain boundaries due toan interruption of the film growth process. Thus, the interface betweenlayers is not necessarily different in chemical composition if it isdifferent in structure.

The term “build axis” or “build direction” is intended to refer to thedeposition axis in the material. For example, as a material is beingdeposited onto a substrate, the thickness or Z-axis of the materialbeing deposited will increase, this is the build axis of the material.

The terms “circumferential” or “circumferential axis” is intended torefer to the radial direction of a tubular, cylindrical or annularmaterial or to the Y-axis of a polygonal material.

The terms “longitudinal,” “longitudinal axis,” or “tube axis” areintended to refer to an elongate aspect or axis of a material or to theX-axis of the material.

The term “film” is intended to encompass both thick and thin films andincludes material layers, coatings and/or discrete materials regardlessof the geometric configuration of the material.

The term “thick film” is intended to mean a film or a layer of a filmhaving a thickness greater than 10 micrometers.

The term “thin film” is intended to mean a film or a layer of a filmhaving a thickness less than or equal to 10 micrometers.

The term “supravalvular” is intended to mean above the cardiac valve,i.e., on the superior or cranial side of a valve.

The term “infravalvular” is intended to mean below the cardiac valve,i.e., on the inferior or caudal side of a valve.

This detailed description of exemplary embodiments makes reference tothe accompanying drawings, which show exemplary embodiments by way ofillustration. While these exemplary embodiments are described insufficient detail to enable those skilled in the art to practice thedisclosure, it should be understood that other embodiments may berealized and that logical changes and adaptations in design andconstruction may be made in accordance with this disclosure and theteachings herein without departing from the spirit and scope of thedisclosure. Thus, the detailed description herein is presented forpurposes of illustration only and not for purposes of limitation.

The cardiac valve 10 of the present invention is preferably made of ametal or pseudometal material fabricated as a single unitary hypotube.Preferably, the single unitary hypotube is formed by physical vapordeposition (PVD) of metal, metal alloy or pseudometal onto a substrateconfigured to form the precursor hypotube structure. Sputter depositionof either thick films or thin films is a preferred form of depositingthe metal, metal alloy, or pseudometal to make the single unitaryhypotube precursor for making the variants of the cardiac valve 10according to the present invention. The deposited hypotube is then lasercut to form a lattice frame structure 12. The lattice frame structure 12is configured to have a main body portion 25 including a plurality ofbiased cells 13, including spring struts 22, valve leaflet portions 24including biasing projections 17, and, optionally, distal anchoringprojections 18.

The main body portion 25, when diametrically expanded, is composed offirst struts 14 that are helically oriented in a first circumferentialdirection along a longitudinal axis of the lattice frame structure 12and second struts 15 that are helically oriented in a secondcircumferential direction along the longitudinal axis of the latticeframe structure 12. The first circumferential direction and the secondcircumferential direction may be opposing or offset from one and othersuch that the first struts 14 and the second struts 15 intersect to formbiased cells 13 of the lattice frame structure 12. As with laser-cuttingintravascular stents, the plurality of first struts 14 and the pluralityof second struts 15 are formed cutting a plurality of slots in thehypotube precursor in a pattern such that the land areas between slotsforms the plurality of first struts 14 and the plurality of secondstruts 15, respectively. A spring strut 22 is provided in the biasedcells 13 within the lattice frame structure 12. Finally, the biasingprojections 17 project longitudinally from at least some of the biasedcells 13, preferably on a terminal row of biased cells at either or botha proximal and distal end of the lattice frame structure 12.

The lattice frame structure 12 is preferably made of a shape memory orsuperelastic metal material, such as, for example, binary, ternary,quaternary, or greater nickel-titanium based alloys. Examples of metalmaterials suitable for use in fabricating the lattice frame structure 12are metal materials material is selected from the group consisting oftitanium, vanadium, aluminum, nickel, tantalum, zirconium, chromium,silver, gold, silicon, magnesium, niobium, scandium, platinum, cobalt,palladium, manganese, molybdenum, hafnium, tungsten, rhenium, iridium,bismuth, iron, and alloys thereof, for example, nickel-titanium,nickel-titanium-cobalt, nickel-titanium-chromium,zirconium-titanium-tantalum alloys, or stainless steel. The foregoingmetal materials are well-suited for physical vapor deposition to formthe metal hypotube and tolerate post-deposition laser cutting andelectropolishing to form the lattice frame structure 12, as well assubsequent shape setting of the valve leaflet portions 24, the main bodyportion 25, and/or distal anchor projections 18.

The valve leaflet portions 24 extends outward along a longitudinal axisof the main body portion 25. The valve leaflet portions 24 areco-extensive with the main body portion 25 of the lattice framestructure 12 and are formed by sections of the plurality of first struts14 and the plurality of second struts 15. Alternatively, the valveleaflet portions 24 may be joined to the plurality of first struts 14and/or the plurality of second struts 15, such as by welding or othermeans of joining known in the art. The valve leaflet portions 24 mayhave different constructs across the different variants of the cardiacvalve of the present disclosure. For example, the valve leaflet portions24 may have a plurality of biasing projections 17 extending distallyfrom an end-most row of the main body portion 25 formed by the firststruts 14 and the plurality of second struts 15. The biasing projections17 are configured to support a polymer valve leaflet formed by a polymercovering over the biasing projections 17.

Each of the variants of the cardiac valve of the present disclosure arecomprised generally of a main body portion 25 and a plurality of valveleaflet portions 24. The main body portion 24 of each variant is formedof a plurality of first struts 14 and plurality of second struts 15. Theplurality of first struts 14 and the plurality of second struts 15intersect one and other to form generally quadrilateral-shaped biasedcells 13 of the main body portion 25. According to one example, theplurality of first struts 14 and the plurality of second struts 15 aredefined by slot patterns formed in the precursor metal hypotube and haveopposing helical orientations about a circumference of the main bodyportion 25. The main body portion 25 terminates, at one end thereof, ina generally sinusoidal or zig-zag configuration formed by the pluralityof first struts 14 and the plurality of second struts 15 definingpetal-like projections from the main body portion 25. At least twospaces are defined between adjacent pairs of the petal-like projectionsat the end of the main body portion 25 and are generally V- or U-shaped.Each of the petal-like projections and at least two of spaces 23 definea valve leaflet portion 24 of the cardiac valve 10.

The variants of the cardiac valve of the present disclosure differ inthe construct or configuration of the valve leaflet portions 24. Forexample, the cardiac valve 10 in FIG. 1 has valve leaflet portions 24that are at least partially formed by the plurality of first struts 14and the plurality of second struts configured to form petal-likeprojections extending from an end of the main body portion 25. The valveleaflet portions 24 have a generally sinusoidal terminal end 11 havingdistal apices 19 and proximal apices 21. The sinusoidal terminal end 11may simply be a relatively wider or thicker portion of a first strut 14and/or a second strut 15 positioned at a most distal terminal end of thevalve leaflet portion 24. The generally sinusoidal terminal end 11 andthe valve leaflet portions 24 form the petal-like projections betweenthe distal apices 19 and the proximal apices 21 that are spaced-apartfrom each other about a circumferential axis of the cardiac valve 10.

The plurality of biasing projections 17 extend along a longitudinal axisof the lattice frame structure 12 and project from an end row of cellsin the lattice frame structure 12. The biasing projections 17 mayproject distally from the generally sinusoidal terminal end 11 of thevalve leaflet portions 24 as illustrated in FIG. 1 . Alternatively, thebiasing projections 17 may intersect at least some of the biased cells13 defined by the plurality of first struts 14 and the plurality ofsecond struts 15 of the sinusoidal terminal end 11 row of the latticeframe structure 12. Optionally, biasing projections 17 are contiguouswith the spring struts 22 and extend beyond the sinusoidal terminal end11 of the lattice frame structure 12. In any of the foregoing describedconfigurations, the biasing projections 17 are joined, coupled, integralwith, and/or co-extensive with at least some of the biased cells 13 andare configured to move radially inward and outward toward a central axisof the cardiac valve 10 under at least partial influence of the biasedcells 13 flexing.

Distal anchor projections 18 project distally from proximal apices 21 ofthe valve leaflet portions 24. The distal anchor projections 18 and/orthe biasing projections 17 may have a width or a thickness that tapersalong their length.

The distal anchor projections 18, the spring struts 22, and the biasingprojections 17 may also be laser cut from the original hypotube or maybe formed as separate components and either deposited onto the latticeframe structure 12 by physical vapor deposition or otherwise joined orcoupled to the lattice frame structure 12.

FIG. 2 depicts a biased cell 13 showing an arrangement of the firststruts 14 and second struts 15 defining four sides of and extendingbetween the four sides of the biased cell 13 and a spring strut 22extending diagonally between the included angles of opposing corners ofthe biased cell 13.

Upon application of a bending force 30 to a corner of biased cell 13, inwhich the spring strut 22 is present, such as by applying opposingforces 32, 34 to open corners of the biased cell, the biased cell 13bends out-of-plane and, upon release of bending force 30 or opposingforces 32, 34, returns to the in-plane position. Both the bending force30 and the opposing forces 32 represent the strain forces that will beapplied to the cardiac valve 10 valve leaflets during operation of thevalves once implanted. The out-of-plane flexion bending of the biasedcell 13 of valve leaflet 24 and recovery of the bending serves to ensureapposition of valve leaflets 24 during valve closure and mechanicalsupport for the valve leaflet 24 during both valve opening and closure.

Upon application of opposing forces 32, 34 orthogonal to a longitudinalaxis of spring strut 22 the apices of the biased cell 13 exert acompressive force onto the spring strut 22, which then flexes under theinfluence of the compressive force and allows the biased cell 13 to flexout-of-plane. Out-of-plane flexion of the biased cell 13, in turn,transfers a motive force to the biasing projection 17 (not shown)causing the biasing projection to deflect inward toward the centralopening of the cardiac valve 10.

As shown in FIG. 1 , a polymer covering or coating is provided on thevalve leaflet portions 24 that subtends the space between pairs ofdistal apices 19 and covers circumferentially adjacent petal-likeprojections of the valve leaflet portions 24. In this manner, the valveleaflet portions 24 are embedded in, covered by, or coated with acoherent polymer material that acts as valve leaflets for the cardiacvalve 10.

The polymer covering 28 also covers to covers the biasing projections 17projecting from the sinusoidal terminal end 11 of the valve leafletsportions 24 and subtends the spaces 23 between adjacent pairs of thebiasing projections 17. The polymer covering 28 is employed to both formthe valve leaflets and achieve valve competency without backflow bloodleakage or regurgitation. The basic properties of the desirable polymerinclude: 1) low thrombogenicity; 2) fatigue resistance; 3) high materialstrength allowing for thin coating or covering of the first struts 14,second struts 15, biasing projections 17, as well as the distal anchorprojections 18, while providing a webbing that subtends open spacebetween the foregoing; and 4) high adhesion strength to the latticeframe structure 12. The polymer is preferably an elastomer that isconfigured to accommodate conformational changes of the valve leafletsections 24 during valve opening and/or closing. Flexiblenon-elastomeric polymers may be employed provided that they havesufficient pliability, conformability, and fatigue resistance tofunction as valve leaflets at small material thicknesses. A wide varietyof biocompatible polymers may be used as the embedding polymer for thevalve leaflets. For example, polytetrafluoroethylene (PTFE), urethanes,such as polyurethane, poly(styrene-b-isobutylene-b-styrene (SIBS), poly(D, L-lactic acid)(PLA) and/or poly (D, L-lactic-co-glycolic acid)(PLGA), and/or polyimides, such as poly(4,4′-oxydiphenylene-pyromellitimide (KAPTON, E.I. du Pont de Nemoursand Company, Wilmington, Delaware) may be useful as the polymer for thevalve leaflets in the transluminal cardiac valve of the presentinvention.

The polymer may be applied by a wide variety of methods, depending uponthe polymer selected, such as, for example, by dip coating, spraying,electrospinning, sintering, or vapor deposition, among other methods.Microporous microstructures in the polymer may be created, such as byelectrospinning or by expansion of PTFE to expanded PTFE (ePTFE) priorto covering the cardiac valve.

Microporous microstructures in the polymer covering may be provided toenhance protein and cellular adhesion to the polymer. Enhanced proteinand/or cellular adhesion to the valve leaflets and/or other portions ofthe cardiac valve may also be achieved by other methods, such as bytexturing, surface charge manipulation, or the like.

The lattice frame structure 12 is preferably made of bare-metal toachieve adequate anchoring against and exclusion of the compressednative valve by pillowing effect. Both the anchoring and exclusion ofthe native valve may be complemented by other securing features on thelattice frame structure 12, such as barbs (not shown). The proximal endof the main body portion 25 may include one or more anchoringprojections 221 (shown in FIGS. 12A, 12B, 13 and 15 ) that project fromthe proximal end of the main body portion 25 and may be shape-set toflare radially outward and open toward the atrial or ventricular outflowto facilitate blood flow from the atrium or ventricle and into andthrough the cardiac valve 10. This proximal flare is also useful duringdeployment to stabilize the valve during a retrograde femoral approachduring implantation. Further anchoring above the valve plane may also beachieved by providing anchoring projections originating at commissuresbetween adjacent valve leaflet sections 24 that are shape set to projectradially or circumferentially outward away from a central longitudinalaxis of the cardiac valve 10.

FIG. 3 is a diagrammatic plan view of a biased cell 300. Biased cell300, like biased cell 13, is bounded by a pair of first strut members304 and second strut members 305 and has a spring strut 322 extendinglongitudinally between the second strut member 305 and positionedintermediate between a pair of first strut members 304. The spring strut322 projects outward from the biased cell 300 along a longitudinal axisthereof. Like biased cell 13, biased cell 300 is formed of a unitary,monolithic hypotube that is machined, such as by laser cutting, with aplurality of slots defining the first strut members 304, the secondstrut members 305 and the spring strut 322. The hypotube may be made ofshape memory, superelastic or plastically deformable, i.e., balloonexpandable materials, as discussed below.

FIG. 4 is a diagrammatic side elevational view of the biased cell 300 ina planar unstrained state where no lateral, in the case of a planarlattice structure, or circumferential, in the case of a tubular latticestructure, force is applied to the biased cell 300.

FIG. 5 is a diagrammatic plan view of the biased cell 300 illustratingexpansion of the biased cell 300 as a result of a lateral force appliedto the second strut members 305 causing the first strut members to opento a diamond shape while exerting an axially compressive strain to thatpart of the spring strut 322 that extends between the second strutmembers 305. As shown in FIG. 9 , the axially compressive strain exertedon spring strut 322, causes the biased cell 300 to deform out-of-planeand the portion of spring strut 322 that projects longitudinally frombiased cell 300 deforms out-of-plane as well.

The out-of-plane deflection of the projecting portion of spring strut322 is advantageously employed in the case of a valve leaflet to act asa spring strut as shown in FIGS. 7A and 7B wherein the spring strutportion of spring strut 322 angularly deflects 310 from the longitudinalaxis of the biased cell 300. When employed as a valve leaflet springstrut, a polymer covering 350 extends between a plurality of springstruts to form the valve leaflet. The polymer covering 350, as shown inFIG. 8 , forming the valve leaflets opens and closes under the influenceof both the blood pressure gradient across the valve, and the springstrut portion of the spring strut 322.

The spring strut 322, when fabricated of a shape memory or superelasticmaterial, is capable of shape setting to form the curvature of the valveleaflets and program the amplitude of deflection of the spring strutportion of the spring strut 322. Similarly, the spring strut 322 can beformed to have one or more tapers or have one or more strain reliefsections that will modulate the amplitude of deflection of the springstrut portion of the spring strut 322 as well as positively affect itsfatigue resistance.

FIG. 9A and 9B illustrate a bicuspid cardiac valve 60 in accordance withthe present invention. FIG. 9A depicts the valve leaflets 66 in a closedposition with the distal ends of each valve leaflet 66 in appositionwith each other. FIG. 9B illustrates the valve leaflets 66 in their openposition creating a generally elliptical blood flow opening 62 thatallows blood flow through the bicuspid cardiac valve 60.

FIG. 10A and 10B illustrate a tricuspid cardiac valve 70 in accordancewith the present invention. FIG. 10A depicts the valve leaflets 76 in aclosed position with the distal ends of each valve leaflet 76 inapposition with each other. FIG. 10B illustrates the valve leaflets 76in their open position creating a generally three-sided hypocycloidblood flow opening 72 that allows blood flow through the tricuspidcardiac valve 70.

FIG. 11A and 11B illustrate a quadricuspid cardiac valve 80 inaccordance with the present invention. FIG. 11A depicts the valveleaflets 86 in a closed position with the distal ends of each valveleaflet 86 in apposition with another valve leaflet 86. FIG. 11Billustrates the valve leaflets 86 in their open position creating agenerally four sided hypocycloid blood flow opening 82 that allows bloodflow through the quadricuspid cardiac valve 80.

FIG. 12A and FIG. 12B, illustrate an infra-valvular perspective view anda supra-valvular perspective view of the cardiac valve 200,respectively, showing a tricuspid valve embodiment as represented bythree petal-like valve leaflet sections about the circumference ofcardiac valve 200. It will be understood that a bicuspid variant of thecardiac valve 200 would have two diametrically opposing petal-like valveleaflet sections about the circumference of the cardiac valve, whereas aquadricuspid variant of the cardiac valve 200 would have four petal-likevalve leaflet sections about the circumference of the cardiac valve.

Each of the anchoring projections 221 and/or the distal anchorprojections 18 may have a rounded distal or proximal terminus onto whicha radiopaque marker may be swaged or otherwise joined or applied. Byproviding radiopaque markers at the rounded distal or proximal terminus,the proximal and distal aspects of the cardiac valve 10 will be visibleunder fluoroscopy during implantation of the cardiac valve 10.Alternatively, or in addition, all or a portion of each anchoringprojection 221, distal anchor projections 18, and/or the first struts14, second struts 15 and/or biasing projections 172 may have aradiopaque material formed therein or thereupon as part of the vacuumdeposition process to make the metal material hypotube. An example ofselective deposition of radiopaque marker materials onto regions of atubular hypotube is disclosed in co-pending, commonly assigned U.S.patent application Ser. No. 17/327,667 filed May 21, 2021, which ishereby incorporated by reference in its entirety.

FIG. 13 is a side elevational view of cardiac valve 200 without thepolymer coating of covering 250 showing the petal-like shape of thevalve leaflet portions 224 and the corresponding petal-like shape of thecollective biasing projections 217. FIG. 14 provides an enlarged view ofa biased cell having biasing projections 217 and spring strut 222. Eachof the spring strut 222 and the biasing projections 221 have a width W2and W1, respectively, that may be the same width or different widths.For example, a portion of the biasing projection 217 that extends frombiased cell 203 may have a narrower or greater width W1 than a width W2of the spring strut 222.

FIG. 15 is a planar view of a one-third circumferential section of thelattice frame structure 202 for a tricuspid cardiac valve in accordancewith an alternative embodiment of the cardiac valve 200 presentinvention. Lattice frame structure 202, like lattice frame structure 12described above, is composed of a plurality of first struts 214, aplurality of second struts 215, spring struts 222, a plurality ofbiasing projections 217, and anchor projections 221. The plurality ofthe first struts 214 have a helical orientation in a first directionrelative to the longitudinal and circumferential axes of the cardiacvalve 200 and the plurality of second struts 215 have a helicalorientation in a second direction relative to the longitudinal andcircumferential axes of the cardiac valve 200. The first direction andthe second direction may be opposing or offset from one and other suchthat the first struts 214 and the second struts 215 intersect to formthe biased cells 203 of the lattice frame structure 202, as exemplifiedin detail in FIG. 15 .

Lattice frame structure 12, 202 is made of a shape memory orsuperelastic metal material, such as, for example, binary, ternary,quaternary, or greater nickel-titanium based alloys. Alternatively,lattice frame structure 202 is made of a plastically deformable, e.g.,balloon expandable metal material, where the spring struts 222 andbiasing projections 217 are elastic. Examples of metal materialssuitable for use in fabricating the lattice frame structure 12, 202 aremetal materials material is selected from the group consisting oftitanium, vanadium, aluminum, nickel, tantalum, zirconium, chromium,silver, gold, silicon, magnesium, niobium, scandium, platinum, cobalt,palladium, manganese, molybdenum, hafnium, tungsten, rhenium, iridium,bismuth, iron, and alloys thereof, for example, nickel-titanium,nickel-titanium-cobalt, nickel-titanium-chromium,zirconium-titanium-tantalum alloys, or stainless steel. The foregoingmetal materials are suited for physical vapor deposition to form themetal hypotube and tolerate post-deposition laser cutting andelectropolishing to form the lattice frame structure 202.

The plurality of biasing projections 217 may originate at an apex of abiased cell 203 and project distally from a distal end of the valveleaflet portion 224. Each of the plurality of biasing projections 217are be in longitudinal alignment with a spring strut 222 and contiguoustherewith. The plurality of biasing projections 217 each have a distalend 206 that may, optionally, terminate in a rounded end 209 configuredto accept a radiopaque marker (not shown) coupled thereto. The pluralityof biasing projections 217, optionally, each have different lengths 207such that the distal end 206 of the plurality of biasing projections 217align to form a generally sinusoidal distal end of the cardiac valve200. This generally sinusoidal distal end of the cardiac valve 200functions to support a polymer coating or covering 250 illustrated inFIG. 16 that forms the valve leaflets of the cardiac valve 200.

Each of the plurality of biasing projections 217 may, optionally, have atapered width that tapers to a relatively smaller width W2 distally thatrelatively larger width W1 at proximal aspects of each of the pluralityof elongate members 108 that emanate from a first strut 214 or a secondstrut 215 at a terminal end of the lattice frame structure 202. Forexample, W2 may be 0.06 mm whereas W2 may be 0.1 mm. Also optionally,the width of each of the plurality of biasing projections 217 may taperto a smaller width W3 where the spring strut 222 bisects a biased cell203. The length, width, and optional taper of each of the plurality ofbiasing projections 217 may be selected based upon the desiredconfiguration of the valve leaflet configuration, the polymer selectedfor the coating or covering 250, and the opening and closing pressuresdesired for the valve leaflets. Finally, the biasing projections 217 mayhave a taper along the build axis of the biasing projections 217.

The plurality of anchoring projections 221 may, optionally, also beprovided at one or both ends of the body portion 225 of the latticeframe structure. The plurality of anchoring projections 221 projectproximally from the cardiac valve 200 and also bisect a proximalterminal end of the biased cell 203. Like each of the biasingprojections 217, the anchoring projections 221 may, optionally, have arounded end 212 configured to couple to a radiopaque marker (not shown).

In use, the cardiac valve 10, 200 is collapsed to a smaller diametricprofile and loaded into a restraining delivery tube of a deliverycatheter. As noted above, the geometry of cardiac valve 10 and/orcardiac valve 200 allow for the smaller diametric profile to be loadedinto a catheter having a 15 F inner diameter of less and 16 French outerdiameter of less. Most preferably the delivery catheter will have a13-15 French inner diameter (4.3 to 5 mm) and a 14-16 French outerdiameter (4.67 to 5.3 mm). The deployed diameter of a cardiac valve 10or cardiac valve 200 in the aorta will be between 30 mm or largerdepending upon the patient. Therefore the single tubular design of thecardiac valve 10, 200 has an 8-10 fold factor of diametric expansion.

It will be appreciated by those skilled in the art that selection ofsuperelastic alloys with greater material properties that nitinol mayalso allow for PVD fabrication of the cardiac valves 10, 200 that arecapable of even smaller collapsed smaller diameters and allow for evensmaller delivery catheter profiles.

As the cardiac valve 10, 200 exits the restraining delivery tube, thelattice frame structure 12, 202 will diametrically expand and the valveleaflet sections 24 will deform radially inward toward the central axisof the cardiac valve 10, 200 all following a pre-determined heat-setconfiguration. The heat set configuration is the resting position of thevalve leaflets and is induced by a bias imposed on polymer valveleaflets by the distal anchor projections 18, 208 such that the freedistal edges of the valve leaflets meet and abut in a commissure in thecenter of the cardiac valve 10, 200. Diametric expansion of the latticeframe structure 12, 202 causes the circumferential expansion of thebiased cells 13, 203. The the spring struts 22 also limit a shorteningeffect induced by the circumferential expansion of the biased cells 13,203.

It will be appreciated that a bicuspid, tricuspid or quadricuspid designof the cardiac valve 10, 200 will require differing lengths of theanchoring projections 18, 221 and the valve leaflet portions 24, 224.For example, since a quadricuspid design has four cusps, each cusp mayhave a relatively lesser length than a tricuspid or bicuspid valvedesign. Where a shorter length of each cusp is possible, the mechanicalload on the anchoring projections 18, 221 and the valve leaflet portions24, 224 will be reduced and the length and/or number of distal anchorprojections 18, 208 may be adjusted in view of a smaller load applied bythe individual valve leaflets.

While the invention has been described with reference to its preferredembodiments, those of ordinary skill in the relevant arts willunderstand and appreciate that the present invention is not limited tothe recited preferred embodiments, but that various modifications inmaterial selection, deposition methodology, manner of controlling thegrain formation within individual layers, across multiple layers, orthroughout the entire thickness of the multi-layer material, anddeposition process parameters may be employed without departing from theinvention, which is to be limited only by the claims appended hereto.

1. A transluminal cardiac valve, comprising a latticed tubular structurehaving a first and second end thereof, a first end of the latticedtubular structure configured as a plurality of undulating sectionsformed by an end row of cells of the latticed tubular structure, aplurality of biasing projections projecting longitudinally from at leastone end of the latticed tubular structure, and at least two valveleaflets comprising at least some of the plurality of biasingprojections extending from cells in the plurality of undulating sectionsand a polymer covering associated with the plurality of biasingprojections.
 2. The transluminal cardiac valve of claim 1, wherein thetransluminal cardiac valve is configured to have a delivery profile lessthan or equal to 15 French.
 3. The transluminal cardiac valve of claim1, wherein cells in the end row of cells have an apex and at least someof the plurality of biasing projections each extend from the apex of atleast some of the end row cells of the latticed tubular structure. 4.The transluminal cardiac valve of claim 1, wherein the polymer coveringextends between the plurality of biasing projections in each of theplurality of undulating sections.
 5. The transluminal cardiac valve ofclaim 4, wherein the at least two valve leaflets are configured to formcommissures there between.
 6. The transluminal cardiac valve of claim 4,wherein the polymer covering is configured to share a mechanical loadwith at least one of the plurality of biasing projections.
 7. Thetransluminal cardiac valve of claim 4, further comprising a spring strutmember in at least some of the plurality of cells in the end row ofcells of the latticed tubular structure wherein each of the at leastsome of the plurality of cells in the end row of cells of the latticedtubular structure having a spring strut member comprise biased cells. 8.The transluminal cardiac valve of claim 4, wherein at least one of thefirst plurality of biasing projections are configured as a structuralsupport for at least one of the at least two valve leaflets.
 9. Thetransluminal cardiac valve of claim 1, wherein each of the undulatingsections are arrayed adjacent to each other about a circumference of thelatticed tubular structure.
 10. The transluminal cardiac valve of claim1, further comprising a plurality of anchor projections projecting fromthe second end of the lattice support structure.
 11. The transluminalcardiac valve of claim 10, wherein the plurality of anchor projectionsare configured to deflect radially outward and anchor the latticedtubular structure to an anatomic valvular annulus.
 12. The transluminalcardiac valve of claim 1, wherein the plurality of biasing projectionsare monolithic with the latticed tubular structure.
 13. The transluminalcardiac valve of claim 1, wherein at least some of the plurality ofbiasing projections have a taper along a length thereof.
 14. Thetransluminal cardiac valve of claim 1, wherein each of the plurality ofbiasing projections have rounded distal ends thereof.
 15. A transluminalcardiac valve, comprising a tubular latticed structure having a valvularend and an anchoring end thereof, the valvular end having a plurality ofbiasing projections extending therefrom, and a polymer covering on theplurality of biasing projections; the polymer covering, and theplurality of biasing projections being configured to form valve leafletsthat are configured to move both toward and away from a centrallongitudinal axis of the tubular latticed structure.
 16. Thetransluminal cardiac valve according to claim 15, wherein the polymercovering subtends space between the plurality of biasing projections.17. The transluminal cardiac valve according to claim 16, wherein thebiasing projections are shape set and configured to deflect the polymercovering toward and away from the central longitudinal axis of thetubular latticed structure.
 18. The transluminal cardiac valve accordingto claim 17, wherein the transluminal cardiac valve is configured to bediametrically collapsed into a delivery catheter having less than a 15French inner diameter.
 19. The transluminal cardiac valve according toclaim 15, wherein the valve leaflet portions are in apposition with oneanother when in a closed position and are configured to achieve valvecontinence and avoid paravalvular leaks.
 20. The transluminal cardiacvalve according to claim 15, further comprising a plurality of anchoringprojections.
 21. The transluminal cardiac valve of claim 15, wherein thetubular latticed structure further comprises a plurality of slots thatopen upon diametric expansion of the tubular latticed structure anddefine a plurality of helically oriented struts in the tubular latticestructure.
 22. The transluminal cardiac valve of claim 21, wherein theplurality of helically oriented struts further comprises a firstplurality of helically oriented struts having a first helicalorientation relative to a longitudinal axis of the tubular latticedstructure, and a second plurality of helically oriented struts having asecond helical orientation relative to the longitudinal axis of thetubular latticed structure, the first helical orientation and the secondhelical orientation being in opposing directions thereby defining theplurality of substantially quadrilateral shaped cells.
 23. Thetransluminal cardiac valve of claim 22, wherein the first plurality ofhelically oriented struts and the second plurality of helically orientedstruts intersect substantially orthogonally relative to each other. 24.The transluminal cardiac valve of claim 15, wherein the latticed tubularstructure further comprises substantially quadrilateral shaped cellshaving longitudinally oriented apices and circumferentially orientedapices relative to the longitudinal axis of the latticed tubularstructure.
 25. The transluminal cardiac valve of claim 15, wherein thevalvular end of the tubular latticed structure has a substantiallysinusoidal shape.
 26. The transluminal cardiac valve of claim 25,further comprising a spring strut in at least some of the quadrilateralshaped cells.
 27. The transluminal cardiac valve of claim 26, wherein atleast one of the plurality of biasing projections is in axial alignmentwith a spring strut.
 28. The transluminal cardiac valve of claim 15,wherein the polymer is selected from the group ofpolytetrafluoroethylene (PTFE), urethanes,poly(styrene-b-isobutylene-b-styrene (SIBS), poly (D, L-lacticacid)(PLA), poly (D, L-lactic-co-glycolic acid) (PLGA), and polyimides.29. The transluminal cardiac valve of claim 28, wherein the polyimidefurther comprises poly (4,4′-oxydiphenylene)-pyromellitimide.